The CSI Effect

The truth about forensic science.

On the evening of March 10, 2003, two New York Police Department detectives, James V. Nemorin and Rodney J. Andrews, were shot and killed in an unmarked police car while attempting an undercover purchase of a Tec-9 assault pistol on Staten Island. The case was significant not just because two officers had died but because the man who was eventually charged with the murders, Ronell Wilson, faced the possibility of becoming the first person in more than fifty years to be executed for a crime in New York State.

The government’s theory was that Wilson, who was with an accomplice in the back seat of the car, shot the detectives during a robbery attempt. Among the evidence retrieved from the crime scene were hundreds of hairs and fibres, and prosecutors enlisted Lisa Faber, a criminalist and the supervisor of the N.Y.P.D. crime lab’s hair-and-fibre unit, to testify at Wilson’s trial, last winter. Under questioning in Brooklyn federal court, Faber said that she had compared samples of fabric from the detectives’ car with fibres found on gloves, jeans, and a baseball cap that Wilson had allegedly been wearing on the night of the crime. The prosecutor asked Faber to describe the methods and equipment she had used to make her analysis. Then she asked Faber what she had found. “My conclusion is that all of those questioned fibres could have originated from the interior of the Nissan Maxima, from the seats, and/or the backrests,” Faber said. She added that in her field “the strongest association you can say is that ‘it could have come from’ ” the source in question.

Faber’s testimony was careful and responsible—and not very significant. She could not say how common the automobile fabric that she had examined is, or how many models and brands use it. Nor could she say how likely it was that the fabric from the car would show up on Wilson’s clothes. Faber used no statistics, because there was no way to establish with any precision the probability that the fibres came from the de-tectives’ car. DNA tests had proved that blood from one of the detectives was on Wilson’s clothes, and based on this fact, as well as on testimony from his accomplice and from Faber, Wilson was convicted and sentenced to death. “Given how much evidence they had in the case, I wasn’t crucial,” Faber told me. “The prosecutors liked the idea of fibre evidence in addition to everything else. Maybe they thought the jury would like it because it was more ‘CSI’-esque.”

“CSI: Crime Scene Investigation,” the CBS television series, and its two spinoffs—“CSI: Miami” and “CSI: New York”—routinely appear near the top of the Nielsen ratings. (A recent international survey, based on ratings from 2005, concluded that “CSI: Miami” was the most popular program in the world.) In large part because of the series’ success, Faber’s profession has acquired an air of glamour, and its practitioners an aura of infallibility. “I just met with the conference of Louisiana judges, and, when I asked if ‘CSI’ had influenced their juries, every one of them raised their hands,” Carol Henderson, the director of the National Clearinghouse for Science, Technology and the Law, at Stetson University, in Florida, told me. “People are riveted by the idea that science can solve crimes.” At the Las Vegas criminalistics bureau where the original version of the show is set, the number of job applications has increased dramatically in the past few years. In the pilot for the series, which was broadcast in 2000, Gil Grissom, the star criminalist, who is played by William Petersen, solved a murder by comparing toenail clippings. “If I can match the nail in the sneaker to the suspect’s clipping . . . ” Grissom mused, then did just that. In the next episode, the Las Vegas investigators solved a crime by comparing striation marks on bullets. “We got a match,” one said. Later in the same show, Nick Stokes (George Eads) informs Grissom, his boss, “I just finished the carpet-swatch comparisons. Got a match.”

The fictional criminalists speak with a certainty that their real-life counterparts do not. “We never use the word ‘match,’ ” Faber, a thirty-eight-year-old Harvard graduate, told me. “The terminology is very important. On TV, they always like to say words like ‘match,’ but we say ‘similar,’ or ‘could have come from’ or ‘is associated with.’ ”

Virtually all the forensic-science tests depicted on “CSI”—including analyses of bite marks, blood spatter, handwriting, firearm and tool marks, and voices, as well as of hair and fibres—rely on the judgments of individual experts and cannot easily be subjected to statistical verification. Many of the tests were developed by police departments more than a hundred years ago, and for decades they have been admitted as evidence in criminal trials to help bring about convictions. In the mid-nineteen-nineties, nuclear-DNA analysis—which can link suspects to crime-scene evidence with mathematical certainty—became widely available, prompting some legal scholars to argue that older, less reliable tests, such as hair and fibre analysis, should no longer be allowed in court. In 1996, the authors of an exhaustive study of forensic hair comparisons published in the Columbia Human Rights Law Review concluded, “If the purveyors of this dubious science cannot do a better job of validating hair analysis than they have done so far, forensic hair comparison analysis should be excluded altogether from criminal trials.”

Last week, a commission on forensic science sponsored by the National Academy of Sciences held an open session in Washington at which several participants questioned the validity of hair and fibre evidence. Max Houck, the director of the Forensic Science Initiative at West Virginia University and the co-author of an important study that reviewed hair analyses by the F.B.I., was fiercely criticized by several members of the commission, including one of the co-chairs, Harry T. Edwards, a senior federal-appeals-court judge. “It sounds like there is a lot of impressionistic and subjective examination going on,” Edwards said, after Houck described the study. “Follow-up examiners repeated [the analyses] and made the same mistakes,” Edwards said. “That’s the scariest part.”

Sir Robert Peel is credited with creating the first modern police force, the bobbies, in London, in 1829, but the transformation of law enforcement, and especially forensic science, into a professional discipline was a haphazard affair. Scientists occasionally took an interest in police work, and courts sometimes accepted their testimony. Oddly, one prominent early figure in the field developed specialties in both bullets and hair, which have little in common except that both are often found at crime scenes. In 1910, Victor Balthazard, a professor of forensic medicine at the Sorbonne, published the first comprehensive study of hair, “Le Poil de l’Homme et des Animaux,” and three years later, in an influential article, he theorized that the grooves inside every gun barrel leave a unique imprint on bullets that pass through it. In the mid-twenties, Calvin Goddard, a New York doctor, began using a comparison microscope, which allows an analyst to examine two slides at the same time, to study bullets. In 1929, he analyzed bullets collected at the site of the St. Valentine’s Day massacre, in which gunmen wearing police uniforms shot and killed six members of George (Bugs) Moran’s gang and a seventh man. Goddard test-fired all eight machine guns owned by the Chicago police and found no match with the bullets used in the crime. Two years later, he examined two submachine guns retrieved from the home of Fred Burke, a sometime hit man for Al Capone, Moran’s great rival. Goddard pronounced Burke’s guns the murder weapons, and the feat so impressed local leaders that they established a crime lab, the nation’s first, and installed Goddard as its director.

The comparison microscopes in the N.Y.P.D. crime lab are more powerful than Goddard’s model was, but many of the techniques the lab uses haven’t changed substantially in decades. Situated in a remote part of Queens, in a sprawling office building that formerly belonged to York College of the City University of New York, the crime lab combines municipal decrepitude and state-of-the-art technology. The seating area in the lobby includes an old minivan bench, complete with a dangling seat belt. There are six analysts in Faber’s hair-and-fibre unit, and each has a polarized-light microscope, which costs about fifteen thousand dollars. In addition, the unit has two comparison microscopes, which cost fifty thousand dollars, but only one phone line, which doesn’t have voicemail. Having worked for the N.Y.P.D. for nearly a decade, Faber has acquired a weary proficiency in the department’s eccentricities. “We have some of the best lab equipment in the country, maybe as good as the F.B.I.,” she told me recently, when I visited her at the lab. “But for the little stuff we have to scrounge.”

Faber’s father, a German businessman, was transferred by his company to Manchester, New Hampshire, in 1966, two years before Lisa was born. She was in junior high school when she became interested in trace-evidence analysis, which includes hair and fibre. “It was the time of the Atlanta child murders,” she recalled, referring to the killings of more than two dozen children and young men in the city between 1979 and 1981. “I would sit there watching the news and see how they were connecting the murders through fibres at the murder scenes. It just fascinated me that you could have a body floating in a river and still find fibre evidence that would connect it to a car.” The trace evidence was critical in the case against Wayne Williams, a twenty-three-year-old aspiring music promoter, who was convicted of two of the murders and sentenced to two life terms. No one has been charged in connection with the other deaths. (In February, following years of unsuccessful appeals by Williams, lawyers for Georgia agreed to allow DNA tests on some of the hair used as evidence in the case. Results of the tests have not yet been reported.)

At Harvard, Faber majored in East Asian Studies. “I still followed murder cases, and the Internet was just getting started not long after I graduated,” she recalled. “So I looked around to see what kind of graduate programs in forensic science there might be around the country. There were four.” One was at George Washington University, where she enrolled. Her first class, in trace analysis, was taught by a former F.B.I. special agent named Hal Deadman. “He passed around materials on that first day, and they were from the Atlanta murders. He had been an investigator on the case. I thought, I can’t believe this. This is perfect for me.” Two years later, having completed a master’s degree, Faber joined the N.Y.P.D., where she earns about seventy thousand dollars a year. A tall woman, who usually wears her long blond hair in a barrette, Faber has an apartment in Greenwich Village, where few other N.Y.P.D. employees live. “No one ever steals my lunch out of the office refrigerator,” she said. “People ask me, ‘That’s all you’re eating—vegetables?’ ”

When a piece of evidence, usually a garment, arrives in Faber’s unit, a junior analyst pats a strip of clear tape on the fabric, to pick up any loose hairs or fibres. The tape strips are then placed face down on a plastic sheet, which is given to a more senior person to study under a relatively low-powered stereo microscope. “I’ve got to do a screening at this point, just to see what might be useful to examine in greater detail,” Faber told me. “As far as hair goes, I’m looking only for head hair and pubic hair, because arm or chest hair doesn’t have enough variation to be useful for comparison. If I see a fibre, I’ll circle it with my green Sharpie. If I see a hair, I’ll circle it in red. A brown circle means I’m not sure what it is. When I’m done, I take my tweezers and remove each hair and fibre and glue them onto slides. Now I’m really ready to begin my analysis.”

According to a long-established practice of hair analysis, the examiners study between twenty and thirty characteristics of each hair. (Only hairs whose roots are intact—typically because they have been pulled from someone’s head—and are in the growing stage have nuclear DNA, which is unique to each person; the vast majority of hairs found at crime scenes lack roots suitable for testing.) “The first thing we look at is pigment—color,” Faber said. “Is there dye or bleach, and how much of it? We like it when there’s dye, because it makes a hair distinctive. Then there is the cuticle, which is like the yellow on a pencil—the outside—and we see if it’s damaged or serrated.” One of the things that make hair analysis so challenging is that a person can have hairs of many different colors on his or her head. Nor can ethnicity be established with certainty on the basis of hair samples alone. “Hair is curly because of diameter variation,” Faber explained. “A black person’s hair typically has a lot of diameter variation. Asian people have little variation, which is what makes it straight.” Faber has hundreds of slides of hair that she has collected from around the world and uses to train junior analysts. “I ask my friends to give me their hair,” she said.

For the Wilson case, Faber examined more than a hundred pieces of evidence, including the victims’ clothes, the suspects’ clothes, and the interior of the car, along with two do-rags and other items seized from the street. From this material, Faber recovered thousands of fibres and hundreds of hairs, each of which had to be assessed under a microscope.

“The examinations involving the car were especially difficult and timeconsuming,” she said. For Faber, the key question in the case was whether she could identify fibres on Wilson’s clothing which resembled those taken from the car. “There were hundreds of fibres that looked stereoscopically similar at lower power magnifications—that is, up to fifty times—but many of them were in fact different in chemical composition,” she said. “I could tell them apart only when I mounted each fibre on a slide and examined it under two hundred to four hundred magnification with a polarized-light microscope. It’s only at that level that you can see what you need to know to identify the chemical composition of the fibre, like whether it’s polyester, nylon, or acrylic.” Once she had eliminated those fibres which could not have come from the car, Faber performed two additional tests on the remaining set: a Fourier Transform Infrared Spectroscopy, to establish and compare chemical composition, and microspectrophotometry, to compare color. Working quickly, Faber said, she could complete perhaps five F.T.I.R. and MSP analyses a day; evaluating all the evidence in the case took her two and a half years.

Several times a year, at the New York Police Academy, Faber lectures about trace analysis in a criminal-investigations course, which generally attracts about a hundred mid-career detectives and other investigators. Earlier this spring, she had the misfortune of appearing late in the three-week course, which meant that the students—about ninety beefy men and six women in an overheated classroom—listened and observed in varied states of consciousness.

“With trace analysis, what we are doing is comparing a ‘q’ to a ‘k,’ ” Faber told the group. “A ‘q’ is a questioned sample from a crime scene—a paint chip on someone’s clothing from a hit and run, a hair in the hand of a murder victim. The source is unknown. The ‘k’ is a known sample—a hair from the autopsy, or one that you take from a suspect. What we do in the trace-analysis unit are comparisons with ‘q’s and ‘k’s. We see if there is a connection.”

Faber’s brief summary defined the dilemma at the heart of forensic science. “There are really two kinds of forensic science,” says Michael J. Saks, a professor of law and psychology at Arizona State University, and a prominent critic of the way such science is used in courtrooms. “The first is very straightforward. It says, ‘We have a dead body. Let’s see what chemicals are in the blood. Is there alcohol? Cocaine?’ That is real science applied to a forensics problem. The other half of forensic science has been invented by and for police departments, and that includes finger-prints, handwriting, tool marks, tire marks, hair and fibre. All of those essentially share one belief, which is that there are no two specimens that are alike except those from the same source.” Saks and other experts argue that there is no objective basis for making the link between a “q” and a “k.” “There is no scientific evidence, no validation studies, or anything else that scientists usually demand, for that proposition—that, say, two hairs that look alike came from the same person,” Saks said. “It’s the individualization fallacy, and it’s not real science. It’s faith-based science.”

Virtually all experts agree about the reliability of DNA evidence. “DNA is based on a well-known technology and scientific principles that have a lot of uses outside the lab and a lot of good validation data,” D. Michael Risinger, a professor at Seton Hall University School of Law, said. “You will typically know what the error rates are. The tests produce actual probability statements about results. It’s real science.” Currently, two kinds of DNA are subject to forensic testing: nuclear DNA and mitochondrial DNA (mtDNA), which is passed from mother to child. Unlike nuclear DNA, mtDNA can be extracted even from hairs that lack roots; though mtDNA tests cannot establish a precise match, they can eliminate many potential suspects. In the past two years, New York authorities have begun conducting mtDNA tests on some evidence.

At last week’s session on forensic science in Washington, Max Houck explained that he and his co-author, Bruce Budowle, a senior scientist at the F.B.I. Laboratory, had used mtDNA technology to test the validity of hair analysis. The authors reviewed the results of a hundred and seventy microscopic hair examinations, which produced eighty associations between “q” and “k” samples. But subsequent mtDNA tests of the hairs showed that in nine cases—more than ten per cent—the samples could not have come from the same person. The number of errors was concerning, Judge Edwards said. According to his calculations, he added, the study’s error rate was actually close to thirty-five per cent. How, he asked Houck, was such a flawed process acceptable?

Houck challenged Judge Edwards’s use of the word “error,” arguing that mtDNA tests provided a way to refine the more general conclusions of microscopic examinations. To illustrate his point, Houck offered an analogy: “Suppose you have an art expert who is looking at three possible van Goghs. He sees that all three are consistent with his style. But then a chemical test comes along that shows two of them were painted after van Gogh died. They’re not van Goghs, but that doesn’t mean that the art expert was wrong about them. They may have been consistent with his style. It’s the same with hair analysis. The subsequent DNA tests don’t mean that the original tests were wrong, just that a more refined test has come along.”

“I don’t think your analogy holds at all,” Edwards said. “Those are real errors, and this is not about art history. My great worry is that there are a lot of people going to jail on bad information.”

Margaret A. Berger, a professor at Brooklyn Law School, added, “We know from a lot of DNA exonerations that they come from bad hair evidence. So the real question raised by your study is whether the courts should ever allow microscopic evidence when there is no DNA to back it up? If there is no mtDNA, I think it should be excluded.”

“Let me ask you this,” Channing R. Robertson, a professor of chemical engineering at Stanford, said to Houck. “Suppose your son or daughter was accused of a crime, and someone came on the stand and gave their qualifications as a hair examiner, and made an association based on microscopic examination, and that led to the conviction of your child. Would you feel that justice had been served?”

After an awkward pause, Houck said, “Not unless there was mtDNA as well.”

Houck’s critics focussed on the possibility of errors by well-meaning hair-and-fibre analysts, but the field has also been beset by scandals. Incompetent or malevolent trace-evidence examiners in several states, including Texas, West Virginia, and Illinois, have produced scores of tainted verdicts, many of which have been uncovered by the Innocence Project, the legal-advocacy group founded fifteen years ago by the defense attorneys Barry Scheck and Peter Neufeld. In a 1987 case involving the rape of an eight-year-old girl, Arnold Melnikoff, the manager of the Montana state crime lab, testified that there was a “less than one in ten thousand chance” that hairs found at the crime scene did not belong to the defendant, Jimmy Ray Bromgard, who was convicted. In 2002, a DNA test of sperm found on the victim’s underwear established Bromgard’s innocence, and several more cases in which Melnikoff testified have been overturned or called into question. (John Grisham’s recent best-seller, “The Innocent Man,” is a nonfiction account of a 1988 murder case in Oklahoma, in which faulty hair analysis, among other things, led to an unjust conviction.) As Faber acknowledges, “There have been horrible cases involving bad hair examiners.” (Last month, the N.Y.P.D. released the results of an internal investigation of its crime lab, which revealed that in 2002 two technicians in the controlled-substances division had failed a department profici-ency test. This information was not reported to the national accreditation body for forensic labs, as the department is required by law to do. The police commissioner, Raymond W. Kelly, replaced the deputy chief who supervised the lab and ordered the creation of an oversight panel.)

Faber and her colleagues, unlike their fictional counterparts on TV, do not visit crime scenes, leaving evidence collection to specially trained N.Y.P.D. officers. Nevertheless, working in the hair-and-fibre lab has given Faber a macabre expertise in city life. She is often called on to examine the clothing of crime victims and suspects, and she has noticed that patterns recur. “They like big clothes,” she told me, referring to the suspects. “We frequently see sizes like 4X.”

Faber has recently taken steps to combine traditional hair and fibre analysis with more modern, and accurate, technology. One day last month, Faber’s colleague Debbie Hartmann was working over a gray Rocawear sweatshirt with tape and tweezers, trying to find hairs to analyze. The sweatshirt had been left behind during a burglary of a house in Queens, and Hartmann was examining it as part of a new project that Faber has implemented in the crime lab. “The city has had a program in place for a long time where we see if we can do DNA testing in every murder and rape,” Faber told me. “But we thought there was no reason not to do burglaries as well. We know that burglars often change their clothes when they’re inside a house, so they don’t look the same coming out as they did coming in. They leave their tools like screwdrivers behind. They eat food and drink the beer in the fridge. They don’t want to leave fingerprints, so they wear rubber gloves and leave them behind. That turns out to be better, because the gloves have DNA from their skin cells, which is better evidence than fingerprints. All of that stuff they leave behind can be tested for DNA, so we decided to do it.” (The N.Y.P.D. crime lab, unlike police departments in many other cities, does no DNA testing itself; Faber and her colleagues send evidence for testing to the medical examiner in the Department of Health, or to private contractors.)

The burglary program, which is known as Biotracks and is funded with a grant from the National Institute of Justice, began in 2003, with a pilot program in northern Queens. It was soon expanded to cover the whole city. As of last week, Faber’s team—it consists of, in addition to Faber, a police sergeant and another criminalist—had analyzed twenty-three hundred and thirty cases and found DNA profiles in fifteen hundred and forty-one of them. The results of these tests have been placed in the F.B.I.’s Combined DNA Index System (CODIS), a database of more than four million DNA profiles from across the country, and almost three hundred suspects have been identified.

Some of Biotracks’ success stories resemble plots of “CSI” episodes. In 2004, Stanley Jenkins, a forty-seven-year-old man who had a criminal record, broke into a residence in Queens and stole jewelry and camera equipment. He used a tissue to wipe away his fingerprints, and no prints were found in the house. But the tissue yielded a DNA sample, and Jenkins was convicted after a trial and sentenced to twenty years to life. The same year, Faber’s team found matching DNA on broken windows in a series of smash-and-grab burglaries at several Manhattan stores, including Tourneau, Coach, and Fendi. Police officers picked up a man named David Gibson because he resembled the suspect in the case, and detectives noticed that he had a bandaged wound on his left hand. They offered to change the dressing and submitted the old bandage for DNA testing, which tied Gibson to the crimes.

In 2005, in perhaps the most bizarre case to date, the Biotracks group took a DNA sample from a soda bottle that a burglar had drunk from at a house in the Bronx. The DNA profile identified a pair of identical twins, Kenneth Williams and Andre Fuller, who were both in the CODIS system because they had criminal records. (Only identical twins have the same nuclear DNA.) It turned out that at the time of the burglary Williams was incarcerated, so when Fuller was arrested in an unrelated case he was charged with the burglary. (The case is pending.) “We never did figure out how twins had different last names,” Faber said.

Faber regards Biotracks as one way of tethering her field to the rigorous science of DNA. “I know everyone wants to go straight to the DNA lab these days, and I don’t blame them,” she said. “But they have to come to us first, and for good reason. Ninety per cent of the hair recovered at a crime scene doesn’t have roots in the right stage of growth. You need roots for nuclear DNA. You might ask, Why is microscopic trace examination necessary? Why not submit all hairs for DNA analysis immediately? But you cannot go to the medical examiner with two hundred hairs. We have so many crimes and hairs. Hairs are everywhere. We couldn’t possibly give every hair to the m.e. We have to screen it first, see if there is a possibility of any kind of DNA test, and then we can send it over.”

There is wisdom, but also some poignancy, in Faber’s efforts to modernize the N.Y.P.D.’s hair-and-fibre unit. The success of the Biotracks program suggests that the best thing hair analysts can do is turn themselves into initial screeners for the test that really matters—DNA. Soon the demand for the kind of testimony that Faber provided in the Ronell Wilson case may be limited, especially if the commission sponsored by the National Academy of Sciences publishes a report harshly critical of the field’s current practices. (In 1992, a similar commission released a blue-ribbon federal report that resulted in the widespread use of DNA evidence in courtrooms.)

Faber is ambivalent about “CSI”—flattered by the attention it has brought to her profession but mindful of the cinematic license taken by the program’s creators. She has noticed, for example, a new kind of applicant for jobs at the crime lab. “They’re waiting for their interviews, and they look like they’re auditioning for a hip profession,” she said. “It’s not the nerdy-looking people anymore. They don’t realize that there is nothing cool or funky about this job.”

A few years ago, when CBS was considering launching the “CSI: New York” spinoff, Faber showed Anthony Zuiker, the creator of “CSI,” and his colleagues around the crime lab. “They were great, really nice, and we were happy that they decided to do the show,” she said. “But in the end they decided to do it in their studio in California.” ♦

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